Metal rods are used as orthopedic prostheses in a variety of applications. One particular application involves rods used as spinal prostheses. In this application, the rod is surgically implanted adjacent to the patient's spine and attached to individual vertebrae with screws, wires, etc. Titanium and stainless steel are most often used as the materials from which these metal rods are made.
When preparing to implant a prosthetic rod, the surgeon will frequently bend the rod to conform to the individual patient's physiological condition. After bending, it is important to be able to determine the angular orientation of the rod. Because the surface finish of these rods is uniform and without markings, surgeons sometimes in the past have had problems in determining the angular orientation of the rod during the implanting procedure.
Time spent determining the angular position of the rod during the surgery is undesirable. This extra time causes problems for the patient who must be in surgery for a longer time, and less importantly, reduces the surgeon's productivity. For this reason, it would be helpful to have markings on prosthetic rods to allow the surgeon to quickly determine the orientation of the rod after bending.
The industry has found it desirable to place a line or other marking the length of the rod to help determine the angular position of the rod. However, a suitable means to apply these markings has not been available.